这是我得到的代码,它只删除列表中的最后一个元素。
delete([_], []).
delete([X|Xs], [X|Last]) :- delete(Xs, Last).
循环应该一直运行,直到原始列表为空并返回新列表。
这与子集有些相似。
delete([Head| Tail], List) :-
delete(Tail, Head, List).
delete([], _, []).
delete([Next| Tail], Previous, [Previous| List]) :-
delete(Tail, Next, List).
?- delete([1,2,3], L).
L = [1, 2].
?- delete([], L).
false.
?- delete([1], L).
L = [].
?- delete(L, [1,2,3]).
L = [1, 2, 3, _].
?- delete(L1, L2).
L1 = [_A],
L2 = [] ? ;
L1 = [_A,_B],
L2 = [_A] ? ;
L1 = [_A,_B,_C],
L2 = [_A,_B] ? ;
L1 = [_A,_B,_C,_D],
L2 = [_A,_B,_C] ?
...
可能是:
delete_last(In, Out) :-
append(Out, [_], In).